Hydraulic coupling

ABSTRACT

This invention relates to an improvement in a hydraulic coupling operating according to the Foettinger principle, with a turbine vane ring and a pump vane ring mounted axially adjacent thereto within a housing, and wherein there is assigned to each of the two vane rings a reversing wheel rotating concomitantly therewith and being open toward the other vane ring, the improvement comprising means for varying the distance between the two vane rings.

United States Patent [191 Eisenmann et al.

HYDRAULIC COUPLING Inventors: Siegfried Eisenmann,

Sigrnaringendorf; Hermann Hiirle, Lauchertha, both of Germany Furstlich Hohenzollernsche Huttenverwaltung, Laucherthal, Germany Filed: Jan. 24, 1972 Appl. No.: 220,249

Assignee:

Foreign Application Priority Data Jan. 26, 1971 Germany .1 P 21 03 598.3

US. Cl 60/353, 60/329, 60/D1G. 5 Int. Cl. F16h 41/10 Field of Search... 60/54, DIG. 5, 353, 329, 330

References Cited UNITED STATES PATENTS 12 1945 Gregg 60/353 Feb. 19, 19741 1,125,593 1/1915 Pinckney 60/54 UX 2,318,187 5/1943 2,359,930 10/1944 2,987,887 6/1961 3,149,465 9/1964 Eshbaugh 60/54 Primary Examiner-Edgar W. Geoghegan Attorney, Agent, or Firm-James E. Bryan, Esq.

[57] ABSTRACT This invention relates to an improvement in a hydrau lic coupling operating according to the Foettinger principle, with a turbine vane ring and a pump vane ring mounted axially adjacent thereto within a housing, and wherein there is assigned to each of the two vane rings a reversing wheel rotating concomitantly therewith and being open toward the other vane ring, the improvement comprising means for varying the distance between the two vane rings.

10 Claims, 3 Drawing Figures PATENTED FEB 1 91974 SHEET 2 [1F 2 HYDRAULIC COUPLING The present invention relates to a hydraulic coupling operating in accordance with the Foettinger principle, comprising a turbine vane or bucket ring, and a pump vane ring mounted axially adjacent thereto, both being accommodated within a single housing, wherein there is assigned to each of the two vane rings a reversing wheel rotating therewith and being open toward the other vane ring. Preferably employed are reversing wheels which are separate structural elements with respect to the housing.

Couplings of this type are known, for example, from the Lueger Lexikon der Energietechnik and Kraftmaschinen (The Lueger Encyclopedia for Energy Technics and Power Engines), Deutsche Verlagsanstalt (German Publishing House) Stuttgart, 1965. In these pumps, the two reversing wheels have the shape of two semi-toroidal surfaces which complement each other to form a complete torus. The vanes extend in both wheels in planes through the common axis of the vane rings and reversing wheels,at least this is preferred in connection with the present invention.

In this type of pump there always will exist a certain amount of slippage as long as the turbine wheel has power input. The extent of the slip, and hence the ratio of the driven speed to the driving speed, depends upon the amount of torque which the turbine wheel receives. One problem arising in such hydraulic couplings is that it is difficult to providefor a regulation of the ratio of the driving speed to the driven speed that is independent thereof or additional thereto. This problem can be solved by a variation of the liquid circulating between the two vane rings. With a complete drainage of the liq-' uid the coupling is separated. When the coupling is filled completely, the ratio of driven speed to driving speed is the maximum.

Such'a regulation has the disadvantage, however, that it is structurally expensive, and even becomes structurally very expensive when the filling and/or drainingof thecoupling is intended to be carried out arbitrarily, or in dependence upon specific parameters of the element which is driven by the coupling.

The present invention provides a coupling of the type described hereinabove which is capable ofthe broadest possible arbitrary controllability of the ratio of driven speed to driving speed and which, in addition thereto, has a simple construction, is virtually maintenancefree, is safe in operation, and can be made with very small dimensions.

Even though the coupling of the present invention is suitable for many purposes where a coupling is desired that has the controllability described above, the preferred field of application of the present invention is the use of the coupling between the fan wheel of a motor vehicle engine and the drive mechanism for this fan wheel, which consistsas a rule of a belt pulley. It is well known that in motor vehicles the required fan wheel output or performance decreases progressively with increasing driving speed, whereas the power input of the fan wheel increases with the third power of the speed. The coupling according to the present invention makes it possible to reduce, to the required extent, the torque which is transmitted fromthe drive mechanism to the fan wheel, and also to reduce the transmitted rate of revolutions, until the fan wheel will rotate, at higher speeds, practically without power input.

In the coupling proposed by, the present invention, the axial distance of the two vane rings from each other is adjustable by'means of a setting or adjusting device. If the two vane rings are displaced or shifted in the axial direction far enough away from each other, the liquid leaving the pump wheelor impeller is no longer forced to directly enter into the turbine wheel. Rather, it can flow within the space between the two wheels back to the pump wheel so that only rellatively small power losses will arise when the vane rings are removed from each other. The problem of the supply and drainage of the liquid is thereby eliminated, and the pump may be constructed as a unit which requires a seal outwardly between rotating parts only at one point thereof.

In the simplest case, one of the vane rings, being rigidly connected with its reversing wheel and the housing, is positioned on one shaft end, whereas the other shaft end projecting into the housing is axially displaceable and carries the other wheel formed by the other vane ring and the other reversing wheel.

If the hydraulic coupling according to the'present invention is constructed in a completely fluid-tight manner, care must be taken to assure that the means for displacing the two vane rings relative to each other within the housing will not change the volume in the housing being available for the fluid while the vane rings are being displaced, or it must change it as little as possible.

It is preferred that the axial position of the two reversing wheels and of one of the vane rings not be changeable with respect to each other, and that the vanes of the other vane ring are axially displaceably guided within slots of the respectively coordinated re versing wheel thereof.

In other words: it is intended of one of the vane rings be adapted to be pulled out, in the axial direction, of the hydraulic coupling proper being enclosed by the two reversing wheels. This type of construction has the advantage that a flow or circulation between the two vane rings is prevented to the greatest possible extent by the reversing wheel from which the corresponding vane ring was pulled out. In addition thereto, a construction of this type also has structural advantages.

Even though, as a matter of. principle, the pump wheel or impeller and also the turbine wheel are constructed as has been explained hereinabove, it is nevertheless preferred that the blades or vanes of the pump vane ring are the vanes which are axially displaceable within the reversing wheel thereof.

The blades being axially displaceable within the reversing wheel thereof are preferably rigidly positioned at the housing, which latter rotates concomitantly therewith, and within which the other vane ring is rotatably and axially displaceably mounted. When the pump blades are rigidly mounted on the concomitantly revolving housing thereof, this affords the advantage that the slippage heat being produced in the pump blades is discharged particularly well to the: housing. The other vane ring is suitably positioned rigidly at the reversing wheel being coordinated thereto, which latter is axially displaceable only together with the other reversing wheel. Even though it is quite possible that the blades being displaceable within the reversing wheel thereof can radially inwardly project, for example from the circumferential wall of the housing, it is preferred that these blades protrude from an end wall of the housing.

that the blades or vanes coupling.

This results in a connection of extreme stability between the housing and the blades.

In the preferred embodiment according to the present invention, which is also particularly suitable for the afore-mentioned main field of application as a fan coupling, the reversing wheel being rigidly connected with its vane wheel or impeller is securely positioned on a bushing on which the other reversing wheel is rotatably, but not axially displaceably, positioned. The bushing is mounted axially displaceably, but not rotatably, on a hollow shaft extending through or into the housing and serving for the drive, or preferably for the power take-off, in which hollow shaft a setting or controlling element is arranged for the axial displacement of the bushing on the hollow shaft. Such a provision results in a compact construction. In the design as a fan wheel coupling, the housing is advantageously driven and carries the hollow shaft of the fan wheel. In this case, there will be mounted in the hollow shaft, as a setting member, an element responsive to the temperature of the air flowing in through the radiator and changing its length when heated, which element, when heated, displaces the bushing against the action of a spring in a sense tending to cause the vane rings to approach each other. In this manner the driven speed is increased. When the air flowing in through the radiator becomes colder again, the elastic force displaces the vane rings in a sense or direction such as to remove the same from each other, whereupon the driven speed of the fan Wheel is reduced.

The coupling according to the present invention will now be described in further detail by way of example and in the preferred embodiment thereof as a fan wheel coupling in connection with a motor vehicle internal combustion engine, and with reference to the accompanying drawings, wherein FIG. 1 is an axial cross-sectional view through a fan wheel coupling according to the present invention, in which the coupling has been shown in the upper half of the figure in the disengaged condition thereof, and in the lower half of the figure in the engaged condition thereof;

FIG. 2 is a cross-sectional view, taken through line II--Il of FIG. 1, with the coupling being in the engaged condition thereof, and

FIG. 3 is a view from the left of FIG. 1 with the fan wheel removed.

The coupling shown comprises a housing consisting of the lid 1 and the bottom portion 2. The two housing parts are connected with each other by means of screws 35. The housing may be flanged to the V-belt pulley, for the drive of the fan of the motor vehicle engine, by means of the screws 36 indicated-in phantom. On the outside, the housing is provided with the cooling ribs 4, 5 and 6 which serve for the dissipation of the heat due to energy losses being produced inside the hydraulic The blades 3 of the pump blade or vanering P are positioned at the end wall of the bottom portion 2. They are preferably made integral with the latter, for example in a high-quality casting process or according to an injection molding process. A driven hollow shaft 7 is rotatably positioned on an inwardly projecting stud 9 of the housing bottom and in a bearing hub 8 projecting outwardly from the lid 1. It is lubricated by the couplingfluid, usually a thin oil. It is prevented from an axial-displacement on the one hand by virtue of its abutment against the housing bottom 2 and, on the other hand, because of a snap ring 16 resting against the bearing hub 8 via an intermediate disc 17. A radial sealing ring 18 seals the driven hollow shaft 7 against the bearing hub 8.

A bushing 19 is axially displaceably positioned on the hollow shaft 7 by means of a keyway 32. The bushing 19 is rigidly connected with the turbine wheel T, for example by means of a press fit. The latter consists of the turbine reversing wheel 33 and the turbine blade or vane ring 20 which is suitably cast in one piece with the reversing wheel 33. As is apparent from the drawing, the turbine wheel extends in'the axial direction approximately over only half of the bushing 19. Rotatably positioned on the other half of the bushing 19 is the reversing wheel 24. An axial displacement of the reversing wheel 24 is prevented by the snap ring 21 and a thrust collar or ring 22. The reversing wheel 24 comprises a plurality of blade slots or vanes 23 extending in axial planes of the wheel, through which during the displacement of the bushing 19 with the reversing wheels 33 and 24 from the above-described disengaged position into the engaged position shown at the bottom of FIG. 1 the pump blades 3 penetrate into the inner space of the pump reversing wheel 24 so that thereafter the two reversing wheels 33 and 24 will cooperate in the conventional manner with the two blade or vane rings 20 and 3 being disposed therein as a Foettinger hydraulic coupling.

It is apparent that, depending upon the displacing position of the bushingl9, the two vane rings 20 and 3 have a different distance from each other, and that the drop in the speed from the pump wheel to the turbine wheel becomes greater the farther away the turbine wheel is from the blade ring 3. By regulating this distance, the ratio of driven speed to driving speed may be adjusted.

Mounted within the bearing stud 9 is a filler screw cap 34 serving for filling the fluid into the hydraulic coupling.

Pressed into the left end (in FIG. 1) of the hollow shaft '7 is the driving flange 11 for the fan wheel 15 with the interposition of a heat-insulating plastic bushing 10. Screws l4 connect the driving flange 11 with the fan wheel proper 15. In the driving flange 11 which is pressed into the hollow shaft 7 with the hub thereof visible in the drawing, a central bore is provided into which an element 12, of an known elastic material is pressed. Heat-transferring ribs 13 of the driving flange ll assure that the air being supplied from the radiator of the motor vehicle due to the air flow and/or the suction of the fan wheel communicates its temperature rapidly to the driving flange l1 and therewith to the elastic material element 12. The latter has a central axially displaceable-operating pin which is progressively more markedly. pushed out of the element 12 with increasing temperature and is adapted to develop considerable forces.

The free end of the operating pin 30 rests against a leaf-type spring 26 which extends through two longitudinal grooves 31 of the hollow shaft 7 and projects with its two ends into an annular groove 25 of the bushing 19 so that, when the pin 30 displaces the leaf-type spring 26 in FIG. 1 from left to right, the bushing 19 and therewith the turbine'wheel and the pump reversing wheel will equally be displaced or shifted, so that as a result the pump vane ring 3 is pushed into or inserted increasingly more markedly into the pump reversing wheel 24. In order to avoid too strong a deflection of the leaf-type spring 26, the latter is reinforced by means of a second leaf-type spring 27. Within the free space between the regulating element 12 of elastic material and the bearing stud 9 inside the hollow shaft 7, there extends a helical spring 28 which counteracts the force of the regulating element 12 of elastic material and which, by way of an annular disc 29, presses against the leaf-type springs, thus seeking by means of the latter to displace the bushing 19 together with the turbine wheel and the pump reversing wheel in FIG. 1 toward the left into the position which corresponds to the disengaged condition of the coupling.

The arrangement of the flat or leaf-type springs 26 and 27 is provided for so that, at very high temperatures, when the axially displaceable coupling parts are in the position shown at the bottom of FIG. 1. a short additional travel or shift of the operating pin 30 toward the right cannot cause any damage.

The coupling shown herein should not be totally filled with operating fluid. There should remain at the inside thereof an air volume of, for example 2 to 3 cubic centimeters in order that the change in volume by means of the operating pin 30 can be absorbed inside the housing.

The fan coupling disclosed and described hereinabove operates in the following manner:

It is assumed that the air flowing in through the radiator is cold. As a result, the operating pin 30 of the regulating element of elastic material is inserted, by means of the helical spring, into the left limiting position thereof, and the coupling will be in the condition shown at the top of FIG. 1. The driven pump vane wheels cannot feed liquid radially outwardly so that torque is not exerted in a significant amount upon the turbine vane wheels, since fluid from the area of the pump vane ring 3 can flow only through the radial outer portions of the slots 23 to the turbine vane ring 20 so that hardly any torque will be exerted upon the latter. The turbine wheel T accordingly rotates very little with respect to the pump wheel ring and the housing. Thus, it also rotates the fan wheel only to a limited degree by way of the hollow shaft 7 and the fan wheel flange 111. When the air flowing in toward the fan wheel through the radiator is heated, the flange 11 also is heated and therewith the regulating element 12 of elastic material. Thereupon, the operating pin 30 of the latter is pushed out toward the right to an extent which corresponds to the temperature of the element 12. Against the action ofthe helical spring, it carries along the turbine wheel and the pump guide wheel or impeller so that the pump vane ring 3 enters or penetrates into the pump guide wheel 24 to a corresponding degree, and so that the portion of thepump vane ring 3 now being present within the pump guide wheel 24 will cooperate with the turbine wheel T in the conventional manner as a Foettinger Coupling. In this manner, the fan wheel 15 is rotated at a considerably increased rate as compared to the rate or speed when cold air flows in, which increased rate does not yet, however, come close to the driving speed or rate of revolutions of the pump wheel. The losses in such an intermediate condition are relatively small. If, in this condition, a stable relationship between the cooling water temperature within the radiator and the output of thefanwheel already has been attained, then this conditionis maintained. If such condition has not been achieved as yet, the turbine wheel together with the pump guide wheel continues to be further displaced toward the right until, in the limiting case, the position shown at the bottom of FIG. I is reached, in whichthe slip of the coupling has assumed the lowest possible value thereof. When the temperature of the in-flowing air decreases again, for example because of the fact that the regulating effect was too strong, or for other reasons, the regulator E2 of elastic or stretchable material no longer can exert any force upon the operating pin 30 thereof, and the helical spring pushes the pin 30 back into the regulator l2 about a corresponding degree. At that time, the turbine wheel with the pump guide wheel is again carried along until a stable condition has once again been reached.

It will be obvious to those skilled. in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifica tions.

We claim:

1. A hydrodynamic coupling, comprising a driving shaft and a driven shaft coaxial with and adapted to rotate relative to one another, a housing adapted to contain a power transmitting fluid fixedly coupled to one of said driving shaft and said driven shaft and rotatable therewith, first vane ring means mounted on said housing and rotatable therewith, a pair of guide wheels having annular concavities with their open portions facing each other to form a chamber, said pair of guide wheels being in fixed axial relation to one another and axially slidable on the other of said driving shaft and said driven shaft, a first of said guide wheels being rotatable about said other of said driving shaft and said driven shaft and having slots formed therein to receive at least a portion of the vanes of said first vane ring at all posi tions thereof, whereby said second guide wheel rotates with said first vane ring, and a second of said guide wheels being fixedly coupled to said other of said driving shaft and said driven shaft and rotatable therewith, sacond vane ring means mounted in the concavity of said second guide wheeland rotatable therewith and setting means operatively coupled to said pair of guide wheels to axially displace said pair of guide wheels relative to said first vane ring whereby the extension of said vanes of said first vane ring into said first guide wheel is varied.

2. A hydrodynamic coupling in accordance with claim 1 wherein the housing is fixedly coupled to the driving shaft and the second guide wheel is fixedly coupled to the driven shaft. 7

3. A hydrodynamic coupling in accordance with claim 1 wherein the pair of guide wheels is mounted on a hollow shaft rotatably mounted within the housing, nonrotatably coupled to one of the input means and the output means and axially slidably coupled to the pair of guide wheels.

t. A hydrodynamic coupling in accordance with claim 3 wherein the hollow shaft is rotatable with respect to the housing, nonrotatably coupled to the output means and axially slidably coupled to the pair of guide wheels.

5. A hydrodynamic coupling in accordance with claim 3 wherein a bushing is nonrotatably and axially slidably mounted on the hollow shaft, the first guide wheel is rotatably mounted on said bushing, the second guide wheel is nonrotatably mounted on said bushing and the setting means is operatively coupled to said bushing to axially slide said bushing on said hollow shaft.

6. A hydrodynamic coupling in accordance with claim wherein the setting means is at least partially mounted in the hollow shaft.

7. A hydrodynamic coupling in accordance with claim 1 wherein the setting means includes a temperature-responsive means.

8. A hydrodynamic coupling in accordance with claim 7 wherein the driven means includes a fan of a motor vehicle and the driving means includes an output means of a motor vehicle engine.

9. A hydrodynamic coupling in accordance with motor vehicle and the driving means includes an output means of a motor vehicle engine.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,792' 585 Dated February 19, 1974 Inventor(s) Siegfried Eisenmann et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Item "Lauchertha" should read Laucherthal Column 6,. line 37, "second" should read first Column 8, lines 4/5 "second" should read first line 8,

"second" should readfirst I Signed and sealed this 16th day of July 1971 SEAL) Attest:

MCCOY M. GIBSON, JR. C. MARSHALL DANN Attesting Officer Commissioner of Patients USCOMM-DC 60376-P69 u.s. GOVEINMENT nnmus omcz: In o-aes-su,

FORM PO-1050 (IO-69) 

1. A hydrodynamic coupling, comprising a driving shaft and a driven shaft coaxial with and adapted to rotate relative to one another, a housing adapted to contain a power transmitting fluid fixedly coupled to one of said driving shaft and said driven shaft and rotatable therewith, first vane ring means mounted on said housing and rotatable therewith, a pair of guide wheels having annular concavities witH their open portions facing each other to form a chamber, said pair of guide wheels being in fixed axial relation to one another and axially slidable on the other of said driving shaft and said driven shaft, a first of said guide wheels being rotatable about said other of said driving shaft and said driven shaft and having slots formed therein to receive at least a portion of the vanes of said first vane ring at all positions thereof, whereby said second guide wheel rotates with said first vane ring, and a second of said guide wheels being fixedly coupled to said other of said driving shaft and said driven shaft and rotatable therewith, second vane ring means mounted in the concavity of said second guide wheel and rotatable therewith and setting means operatively coupled to said pair of guide wheels to axially displace said pair of guide wheels relative to said first vane ring whereby the extension of said vanes of said first vane ring into said first guide wheel is varied.
 2. A hydrodynamic coupling in accordance with claim 1 wherein the housing is fixedly coupled to the driving shaft and the second guide wheel is fixedly coupled to the driven shaft.
 3. A hydrodynamic coupling in accordance with claim 1 wherein the pair of guide wheels is mounted on a hollow shaft rotatably mounted within the housing, nonrotatably coupled to one of the input means and the output means and axially slidably coupled to the pair of guide wheels.
 4. A hydrodynamic coupling in accordance with claim 3 wherein the hollow shaft is rotatable with respect to the housing, nonrotatably coupled to the output means and axially slidably coupled to the pair of guide wheels.
 5. A hydrodynamic coupling in accordance with claim 3 wherein a bushing is nonrotatably and axially slidably mounted on the hollow shaft, the first guide wheel is rotatably mounted on said bushing, the second guide wheel is nonrotatably mounted on said bushing and the setting means is operatively coupled to said bushing to axially slide said bushing on said hollow shaft.
 6. A hydrodynamic coupling in accordance with claim 5 wherein the setting means is at least partially mounted in the hollow shaft.
 7. A hydrodynamic coupling in accordance with claim 1 wherein the setting means includes a temperature-responsive means.
 8. A hydrodynamic coupling in accordance with claim 7 wherein the driven means includes a fan of a motor vehicle and the driving means includes an output means of a motor vehicle engine.
 9. A hydrodynamic coupling in accordance with claim 1 wherein the setting means includes a temperature-responsive member which changes in length in response to temperature variations, a spring means normally biases the pair of guide wheels away from the second vane ring and the lengthening of said temperature-responsive member overcomes the biasing of said spring and moves said pair of guide wheels toward said second vane ring.
 10. A hydrodynamic coupling in accordance with claim 9 wherein the driven means includes a fan of a motor vehicle and the driving means includes an output means of a motor vehicle engine. 